Hi! I want to screw around with making a light collimator using a parabolic reflector. I was wondering if anyone might have an old direct tv (or similar) dish laying around that they might be willing to donate for mad science. Or a couple bucks. Let me know if you’ve got a dish you’re not using!
(The other option is fresnel lenses, or a hybrid approach to minimize apparatus depth)
I’d be curious to hear about what you have planned. I’ll assume that you are not just interested in setting things on fire. I would invite you to stop by our weekly Science Sunday gathering at 3pm.
I’m not sure you will be able to get a sufficiently smooth surface trying to mirror a TV dish to do science (assuming you are interested in visible light). If you happen to be interested in Schlieren photography, that’s actually something we’ve talked about as a possibility for one of our projects (visualizing acetone vapor flow due to its higher density than air)
Well, as we all know, everything you see on the Internet is true. That said, I saw a video of a guy a while back who had made a collimator to mimic the parallel nature of sunlight (also passing through light through a filter of liquid with a tiny bit of some kind of soap to give it the “warm” slight diffusion. The fluid was trapped between two pieces of plexiglass).
As a novice stained glass enthusiast, the notion of collimated, fake sunlight appealed to me. I know there are lenses that can bounce the light around to achieve collimation, but I assume the quality of an $8 lens from Amazon isn’t going to be great. I also wanted to reduce the distance the light source needs to be from any lens or reflector (thereby minimizing depth of whatever this ends up being) by pointing the light at a parabolic reflector from a place that is NOT the focal point (I was thinking it could be closer than the focal point, but it’s been over a decade since I took optics in college so I don’t know off the top of my head if this will work, maybe I’ve got the idea backwards) and bouncing the light then into a fresnel lens or something, thereby reducing the depth of the apparatus.
I’m probably completely wrong about that “optimization” but the basic idea with just the reflector or fresnel lens should work. It doesn’t need to be perfect, either.
Also please forgive weird typos, my phone’s touch calibration is hot trash.
Ahh, for lighting purposes, a photographic parabolic umbrella light will do what you are looking for. I think Digital Media might have some.
We have one. We’re getting ready to have a new roof put on. If you want it right away you’re welcome to get it now off the roof (1story in Carrollton) or wait until the roofers remove it.
That would be great! But let me know when the roofers get it down, my back is screwed up enough without falling off a ladder!
Will do. There’s some trim work that needs to be done first.
| eapayson
December 10 |
- | - |
That would be great! But let me know when the roofers get it down, my back is screwed up enough without falling off a ladder!